AWS S3 Buckets do not have at-rest server side encryption enabled to protect sensitive data.
In AWS Console -
In Terraform -
For current AWS Provider versions:
For AWS Provider versions prior to 3.x (deprecated):
References:
https://docs.aws.amazon.com/AmazonS3/latest/userguide/serv-side-encryption.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket#server_side_encryption_configuration
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_server_side_encryption_configuration